Production process control system

ABSTRACT

A system is provided to enable communication between a plurality of terminal devices and a central device connected thereto. The central device includes a communicating element which takes initiative and performs communication with a plurality of terminal devices in a predetermined order by scanning the same and also detects any abnormality of a terminal device in communication therewith. An abnormal terminal table is provided in the system for registering any abnormality of any of the terminal devices. The system contains an element for checking whether an abnormality is registered for a particular one of the terminal devices by reference to the abnormal terminal table. Communication is established with that particular terminal device, the checking element then generating a corresponding output. A control element is provided responsive to the output of the checking element to cause communication processing with that particular terminal device when no abnormality is registered. The control element also causes the checking element to check the next terminal device for abnormality registration when any abnormality is registered, a registering element also being provided to register any detected abnormalities in the abnormal terminal table. In one aspect of this invention, the central device also includes a display unit for displaying data pertaining to a terminal device detected as having an abnormality.

This is a continuation of Ser. No. 292,457 , filed Dec. 30, 1988, nowabandoned, which is a division of Ser. No. 171,226, filed 3/22/88, nowU.S. Pat. No. 4,878,176, which is a continuation of Ser. No. 730,185,filed 5/3/85, now abandoned.

TECHNICAL FIELD

The present invention relates to a production process control systemsuited to a production operation which involves multiplicities ofprocesses, work areas and workers for controlling the amount of workdone as classified by the processes, works areas and workers.

BACKGROUND OF THE INVENTION

Typical of factory automation is a system which comprises thecombination of conveyor system and robot system. With such a system, amultiplicity of workplaces are provided along the conveyor line, andeach workplace is provided with a robot for performing the work for theprocess assigned to the workplace. The parts or articles to be processedare transported by the conveyor at a specified speed to be worked on asspecified by robots at various workplaces and progressively made intofinished products. Such an automated system is suitable for a product tobe made by a plurality of processes for which approximately equalperiods of time can be set to execute the contemplated work, or to aproduct for which processes can be set with assignment of approximatelyequal periods of working time. When worker are used instead of robots,each process may be such that, on the average, different persons canperform the contemplated work with approximately equal periods of time.

However, there are various kinds of products which are difficult to makeby such typical factory automation, for example, a product which ismanufactured by a series of processes including processes wherein thework efficiency is dependent largely on the ability of the worker, and aproduct which involves difficulty in assigning approximately equalworking periods to the processes therefor. Stitched products areexamples of such products

In the case of any product, however, the improvement of productivity,which is one of the important goals, requires proper recognition andanalysis of the flow of material through the production process.Further, "since the overall efficiency depends on the capability andproficiency of the workers it is also important"; to recognize andanalyze the productivity of the individual workers. "Where such typicalfactory automation is difficult to apply"; difficulties are alsoencountered in obtaining at one location the data relating to the amountof work done as classified by workplaces (work areas) or processes,because the time required for work or work efficiency differs fromprocess, to process, and the material to be worked on therefore does notflow at a constant speed from process to process. In some cases, workersmay change for personal reason or to assure a balance between processes,in the amount of work done, or some workers may be located at other worksites. Thus, it is also difficult to obtain data as to the amount ofwork done by each worker.

DISCLOSURE OF THE INVENTION

The main object of the present invention is to provide a productionprocess control system which is suited for controlling the amount ofwork done as classified by processes, work areas and workers.

The production process control system comprises a plurality of terminaldevices and a central device connected to the terminal devices, each ofthe terminal devices at least including means for counting the amount ofwork done (i.e. output), means for entering a worker identifying codeand means for transmitting the counted output and the entered workeridentifying code to the central device. The the central device at leasthas means for performing communications with each terminal device andmean for storing the output and the worker identifying code transmittedfrom the terminal device as associated with each other.

Since each terminal device has output counting means and workeridentifying code entering means, and since each output and eachidentifying code are transmitted to the central device, it is possiblefor the central device to recognize the output of each worker. Theworker identifying code is entered by each terminal device, so that theoperator at the central device need not enter a change of worker to thecentral device every time such a change occurs.

Preferably, a terminal device is provided at each work area where aworker performs work. The central device sets a process as associatedwith the work area or terminal device, and stores the output and theworker identifying code transmitted from the terminal, as associatedwith the set process and the work area or terminal device. This makes itpossible for the central device to control the output of each process orwork area, in addition to the recognition of the output of each worker.This further permits the control of line balance.

If it is possible for one terminal device to handle a plurality of workareas and the identifying codes and outputs of a plurality of workers,the terminal device of course need not be provided for every work area.Conversely, one process can be set for a plurality of work areas or aplurality of terminal devices. An arrangement of ten numerical keys,card reader and various other means is usable as the means for enteringthe worker identifying code. Various features of the invention willbecome apparent from the following description of an embodiment forproducing stitched articles, with reference to the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows a conveyor system installed within a sewingfactory;

FIG. 2 is a perspective view showing a conveyor branch;

FIG. 3 is an enlarged perspective view showing an outgoing rail of theconveyor branch and a temporary stopping device for carriers;

FIG. 4 is a partial vertical sectional view of a stopping device; FIG. 5is a block diagram showing the outline of a communication system;

FIG. 6 is a block diagram showing the outline of a communication unit;

FIG. 7 is a perspective view showing the appearance of a terminaldevice;

FIG. 8 is a sectional view showing a holder for a bar code reader;

FIG. 9 is a block diagram showing the electrical construction of theterminal device;

FIG. 10 is a plan view showing a product name-process name card and aworker name card;

FIG. 11 is a flow chart showing the usual operation of the terminaldevice;

FIG. 12 is a flow chart showing interrupt processing to be done uponsensing withdrawal of the bar code reader;

FIG. 13 is a block diagram generally showing the electrical constructionof a central device;

FIG. 14 is a flow chart schematically showing the operative relationbetween the central device and the terminal device;

FIG. 15 is a flow chart schematically showing output processing by thecentral device;

FIG. 16 shows an example of a display on a CRT in process setting;

FIG. 17 shows part of a base data area in a data memory in the centraldevice;

FIG. 18 is a flow chart generally showing the usual output (amount ofwork done) display processing;

FIG. 19 shows an example of display on the CRT showing output byproducts;

FIG. 20 shows an example of a CRT image for displaying output byprocesses;

FIG. 21 shows an example of a CRT image for displaying output byprocesses on an enlarged scale;

FIG. 22 shows an example of a CRT image for displaying output byworkers;

FIG. 23 is a flow chart generally depicting the processing fordisplaying work output.

FIG. 24 shows an example of data relating to process output with time,as printed out by a printer;

FIG. 25 is a flow chart generally showing processing for estimatingprocess outputs;

FIG. 26 shows an example of CRT image for displaying estimated processoutputs;

FIG. 27 is a flow chart generally showing line balance check processing;

FIGS. 28 and 29 show examples of images to be shown on the CRT in linebalance check processing;

FIG. 30 shows an example of worker daily report printed out by a printerin worker daily report output processing;

FIG. 31 shows a proficiency data storing area provided within the memoryof the central device;

FIG. 32 shows an example of CRT image in worker proficiency outputprocessing;

FIG. 33 shows an abnormal terminal table provided within the memory ofthe central device;

FIG. 34 is a flow chart generally showing the communication process tobe executed by the central device with the terminal device; and

FIG. 35 is a flow chart generally showing processing for an abnormalterminal device.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The Conveyor System:

FIG. 1 shows a conveyor system installed in a sewing factory. Theconveyor, which is of the overhead type, is shown in detail in PublishedExamined Japanese Patent Application SHO 52-1193. The conveyor systemincludes some endless main lines 11, 12, 13, etc., which are connectedtogether by connecting lines 19. As shown in FIGS. 2 to 4, carriers 25have wheels 61 which are rollable on a rail 17 constituting the mainline. The main line rail 17 is internally provided with a drive belt 15coextensive therewith and having engaging portions 16 at a predeterminedspacing. The carrier 25 is movable along the main line by being pushedby the engaging portion 16 on the belt 15 which is driven at a constantspeed at all times.

The main lines 12 and 13 have connected thereto a multiplicity of branchlines 22 at suitable locations. The branch lines 22 have stations S1,S2, S3, . . . for articles to be transported, i.e. products, or parts orsemifinished products to be stitched Sewing operation is conducted atthese stations. There is also a station 23 having a plurality of supplybranch lines 23 for supplying a plurality of parts to the station sothat the plurality of parts are sewed together into a segment of productor a semifinished product.

The main item of data to be controlled by the sewing process controlsystem is the amount of work done. The amount of work done, which willbe referred to as "output;" is the number of segments of products,semifinished products, products or the like. The output of eachindividual worker is called "individual output," the output of eachprocess is the "process output," and an output classified; according tothe kind of product is the "product output." Further, the degree ofvariation of a process output is called a "line balance." Since theoutput is thus analyzed from several viewpoints, an identification codeis necessary for discriminating different outputs from one another.

The number assigned to identify each work area, i.e., a workplace, isused as an output identification code. (The number will hereinafter bereferred to as an "area code.") A work area 32 is provided for eachstation on the conveyor branch line 22. There are also work areas 33which are provided at locations other than the conveyor branches. A workarea 33 is a place where a fabric is worked on for a small part, such aspocket or the like. Not only the main lines 12 and 13, but also the mainline 11 may be provided with branch lines as indicated by broken linesin the figures. These branch lines are also provided with work areas 35.Such work areas 32, 33 and 35 are assigned respective area codes A1, A2,A, . . . . , A101, A102, . . ., which are different from one another.

It appears possible to assign, for example, to a sewing machine table,other work table or conveyor branch station, an output identificationcode other than the area code. However, it is likely that the worktablewill be moved along with the worker or for a change of process, so thatthe code is not fully useful as an unchanged identification code.Further, the station, which belongs to the conveyor system, is providedonly for a branch line. There is no station for the work area 33 whichis irrelevant to the branch line. With use of codes assigned tostations, it becomes impossible to control the output of a process whichis irrelevant to the conveyor system. Because the work areas can befixedly predetermined within the sewing factory, the work area codes areuseful as identification codes which are most suited to the sewingprocess control. The process control encounters no problem whatever evenif the process is so designed that no work is performed at a certainwork area.

With reference to FIG. 1, the work areas 32, 33 and 35 are each providedwith a terminal device 41 for controlling the process concerned. Thebranch lines 22 are provided with switches 42 at the work areas 32 forcounting the output automatically. When a part or the like is worked onat the work area 32 or 35 and sent to the main line via the branch line22, the switch 42 is turned on. The work area 33 which is irrelevant tothe conveyor branch line 22 is also provided with an output countingswitch 43. The switch 43, which is a manual one, is turned on by theworker at the area 33 when one unit of the parts or the like has beenworked on. The switch 43 may be one which is actuated by worker's thefoot. The output signal from switches 42 and 43 is used for the terminaldevice 41 to count the number of worked parts or the like (output). Theswitch 43 at the work area 33 need not be actuated for every workingoperation but may be manipulated every time a number of parts or pieceshave been worked on (e.g., for an output of 10 pieces). Alternatively,the switch 43 may be one, such as an arrangement of ten numerical keys,for directly entering numerical data, i.e., an output during a specifiedperiod of time.

FIG. 2 shows an example of conveyor branch line 22. The branch line 22comprises an incoming rail portion 51 for guiding the carrier 25 fromthe rail 17 of the main line 12 to the station, and an outgoing railportion 52 for returning the carrier 25 from the station to the mainrail 17. As seen in FIG. 4, the carrier 25 comprises an axle 62, wheels61 rotatably mounted on opposite ends of the axle 62, a hanger 64extending downward from the axle 62 for holding at its lower end thearticle to be transported, such as a part, semifinished product orproduct, and an address portion 63 fixed to the axle 62 outside one ofthe wheels 61. The address portion 63 serves to store the code of thedestination station (work area) for the carrier. The code can be changedas desired. Although a magnetic record medium is usable for the addressportion 63, the address portion is preferably a mechanical means, suchas one which comprises a plurality of movable small pieces.

With reference to FIG. 2, at the location where the incoming rail 51branches off the main rail 17, the starting end of the rail 51 isprovided with a pivotally movable arm 53. At a location upstream fromthe branching portion with respect to the direction of advance of thecarrier 25, the main rail 17 is provided at one side thereof with anaddress sensor 55 for detecting the address expressed on the addressportion 63. When the address indicates the station to which thebranching rail 51 extends, the pivotal arm 53 is moved into contact withthe rail 17, permitting an advancing carrier 25 to pass over the arm 53onto the incoming rail 51. While rollingly advancing on the rail 51under gravity, the carrier 25 is stopped by a temporary stopping device56 which is disposed on an intermediate portion of the rail 51. If theaddress on the carrier 25 indicates other station, the pivotal arm 53 isheld away from the rail 17, permitting the carrier 25 to continue itsuninterrupted advance on the main rail 17.

An address setting device 57 is provided at the junction (where thestation is located) between the incoming rail portion and the outgoingrail portion 52. The address of the station to which the carrier 25 isto be forwarded next is set on the address portion 63 of the carrier 25by the device 57. The carrier 25, with the address of the nextdestination set thereon, then ascends the outgoing rail 52 and returnsto the main rail 17 via a pivotal arm 54 provided at the forward end ofthe rail 52. The outgoing rail 52 is provided with temporary stoppingdevices 58 and 59 at two locations.

The foregoing process control terminal device 41 is attached, forexample, to a post 60 for supporting the rails 51 and 52. The post 60 issupported by an upper portion of the building of the sewing factory. Theplace where the station is provided is the work area 32, in which aworktable is placed for a sewing machine or the like. The worker at theworktable performs some work on the article sent forward by the carrier25.

FIGS. 3 and 4 show the temporary stopping device 59 at the second stageas well as the means for driving the carrier 25. The stopping device 59has a frame 70, which is fixed at a lower mount portion 71 to the bottomof the rail 52 with screws. The frame 70 comprises the mount portion 71,an upstanding portion 72 extending upward from one side of the mountportion 71, a top portion 73 extending horizontally from the upper endof the upstanding portion 72, and a stopper support 74 including twoparallel pieces which extend downward from the free end of the topportion 73. A stopper 76 is pivotably supported by a pin 75 on thestopper support 74 and biased by a spring 77 so that its lower end isdirected downward. Attached to the support 74 is a member 78 by whichthe carrier 25 is prevented from falling off the rail 52 while runningthereon.

A groove 79 is formed in a lower part of the frame upstanding portion 72on the inner side thereof. The groove 79 has a smaller width at itsopening than at its inner portion. A projection defining the groove 79has a stepped portion 79a. The aforementioned output counting switch 42,which is a limit switch, is fixedly provided between the stepped portion79a and the mount portion 71 by being biased by a spring 69 An actuator68 has a supported end 68b which is nearly circular in cross section Thesupported portion 68b is rotatably fitted in the groove 79. The otherend of the actuator 68 extends to a position slightly above and close toa wheel supporting portion 52a of the rail 52. The actuator 68 is formedon its lower surface with a projection 68a, which bears on the plungerof the limit switch 42. While the carrier 25 is not positioned where thelimit switch 42 is provided, the limit switch 42 remains off. When thecarrier 25 passes this location, the wheel 61 of the carrier 25depresses the supported end of the actuator 68, causing the projection68a to lower the plunger to turn on the limit switch 42. When required,the wheel supporting portion 52a of the rail 52 may be partly cut out,with the other end of the actuator 68 made accessible to the cutout. Thearrangement can be so adapted that the limit switch 42 will be turned onby the contact of the actuator 68 with a portion of the carrier 25 otherthan wheel 61. Furthermore, the limit switch serving as the outputcounting switch can be replaced by a photoelectric switch or the like,the optical path of which is blocked by the carrier 25 or on whichreflected light is made incident by the carrier.

The other temporary stopping devices 56 and 58, although similar to thedevice 59 in construction, are not provided with the switch 42. Theaddress setting device 57 is provided with a stopper the same as thestopper 76.

The rail 52 (as well as the rail 51) is hollow and has a slit 52b in itsupper side Inserted in the hollow portion of each of the rails 51 and 52is a drive chain 66 extending approximately from the temporary stoppingdevice 56 to a location a small distance upstream from the pivotal arm54. Drive pawls 67 are pivotably mounted on the drive chain 66 asarranged at a suitable spacing. The drive pawl 67 is held in an uprightposition by an unillustrated spring. The drive chain 66 is driven by apneumatic or hydraulic cylinder or some other drive means (not shown).

With reference to FIG. 2, on completing work on the article (part,semifinished product, product or the like) to be transported, the workerplaces the article on the hanger 64 of the carrier 25 or causes thehanger to grip the article and depresses a forward button (not shown) onthe address setting device 57, whereupon the drive chain 66 is driven,causing drive pawls 67 to push the axles 62 of the carriers 25.Consequently, the carrier at the position (station) of the addresssetting device 57 is forwarded to the position of the temporary stoppingdevice 58 at the first stage, the carrier at the temporarily stoppedposition in the first stage to the position of the second-stage stoppingdevice 59, the carrier at the temporarily stopped position in the secondstage onto the main rail 17 via the pivotal arm 54, and the leading oneof the carriers at the position of the stopping device 56 to thestation. The carrier reaching the position of each of the devices 58 and59 pushes up the stopper 76 against the force of the spring 77, passesby the stopper 76, retracts some distance to the position of the stopperunder gravity when the pushing force of the chain 66 thereafter ceasesto act and is held in this position by the stopper 76. The carrier atthe position of each of the stopping device 56 and the address settingdevice 57 pushes up the stopper there, passes the position and advancestoward the next position. At this time, the address of the nextdestination station is set on the address portion 63 of the carrierconcerned by the address setting device 57. When the chain 66 returns tothe original position, the drive pawls 67 passing the positions of thecarriers are pushed into an inclined position by the carrier axles 62.

The counting switch 42 is provided within the second-stage stoppingdevice 59 as indicated in broken lines in FIG. 3 and is disposedslightly below, i.e., toward the first-stage stopping device from, theposition of the carrier 25 stopped by the stopper 76. Accordingly, theswitch 42 is turned on slightly before the carrier at rest at thefirst-stage stopped position passes the position of the stopper 76 whenthe carrier advances toward the second-stage stopped position. Ofcourse, a carrier passing by the stopper 76 of the second-stage stoppingdevice 59 will in no way turn on the switch 42 again. A carrierforwarded from the station to the first-stage stopped position will notturn on the switch 42 either. The switch 42 is turned on only when thecarrier is sent from the first-stage stopped position to thesecond-stage stopped position.

It is likely that the worker, thinking that he has completed thespecified work on a workpiece, will send the workpiece and the carrierat the station to the first-stage stopped position and thereafter becomeaware that the workpiece has not been completely worked on In such anevent, the worker will remove the carrier at the first-stage stoppedposition from the rail 52 and perform the unfinished work. If the outputcounting switch 42 were disposed between the station and the first-stagestopped position, the switch 42 would be turned on by the carrier andfurther turned on again when the carrier with the completed workpiece isforwarded from the station to the first-stage stopped position againafter the unfinished work has been completed. Thus, the switch 42 willbe turned on twice by the single workpiece, failing to assure accuratecounting of output.

With the present system, the counting switch 42 is disposed between thefirst-stage stopped position and the second-stage stopped position. Itis generally after a work operation and until the finishing of thesubsequent work operation that the worker becomes aware of uncompletedwork. With the present system, therefore, the likelihood that the switch42 will be turned on twice owing to the above-mentioned worker's erroris greatly reduced. The switch 42 may be at any location beyond thefirst-stage stopped position As indicated at SW in FIG. 2, the switch 42can be disposed at any location within the section of from slightlyabove the first-stage stopped position to a position close to thepivotal arm 54.

Stitched products, such as shirts, trousers or sportswear, are completedby subjecting suitably cut pieces of fabric to a plurality of specifiedprocesses, e.g., about 10 to 100 processes. Each of the work areas 32,33 and 34 shown in FIG. 1 is assigned the work of a process of a singleproduct. Some processes require much labor and time, so that the work ofsuch a process may be carried out at a plurality of work areas. Aplurality of processes, each involving simple work, may be conducted ata single work area. In this case, the name of a typical process or acollective name of a number of processes may be given to the work areato simulate a single process.

In any case, in producing a stitched article, a process and a worker forthe production are assigned to each work area. The order of arrangementof work areas need not always correspond to the order of the processes,because the desired address can be set on the carrier by the addresssetting device 57 at each conveyor branch station to guide the carrierto the desired station (work area). The processes for different productscan of course be set for the conveyor system shown in FIG. 1 if thenumber of work areas is sufficient.

With reference to FIG. 1, a piece cut off from a fabric for sewing at acutting area 31 is gripped by a carrier, which is given the address forthe first process and then delivered from a branch line 21 to the mainline 11. The carrier is transferred from the main line 11 to the mainline 12 via the connecting line 19 and forwarded to a branch line 22 forthe first process. The piece is worked on at a work area 32 for thefirst process and gripped by the carrier, to which the address for thesecond process is given. Via the branch line 22, the carrier is returnedto the main line 12 and guided to a branch line 22 for a work area wherethe work for the specified second process is to be performed. In thisway, the carrier carrying the piece is led through branch lines 22 and23 for the work of specified processes in the order of processes via themain lines 11, 12 and 13, and the piece on the carrier is progressivelymade into a finished product. The finished product is carried along themain line 11, led to a main line 18 in a product stock area 34 andtransferred to a specified branch line 28 therein for storage. A part orpiece worked on at the work area 33 irrelevant to the conveyor system iscarried by a worker to the work area 32 where work is conducted with useof the piece.

The main lines 11, 12 and 13 each have an independent loop of thetransport path. Accordingly, an address sensor such as the sensor 55 maybe provided at the junction of the connecting line 19. The addresssensor will serve to discriminate the addresses concerned with therelevant main line from those of the stations belonging to the othermain lines The main lines 11, 12 and 13 may be combined to form anoverall single loop of the transport path, such that the carriertransferred from the branch 21 to the line 11 invariably passes throughthe line 12, then returns to the line 11 again, subsequently passesthrough the line 13 and thereafter returns to the line 11. In this case,no address sensor will be needed at the junctions of the connectinglines 19. Although FIG. 1 shows several main lines, the conveyor systemmay, of course, consist of a single main line.

The Communication System

FIG. 5 shows that the terminal devices 41 provided for the work areas32, 33 and 34 are connected to a central device 40 to perform requiredcommunications with the central device 40. To avoid transmission errorsdue to noises electromagnetically induced by fluorescent bulbs, sewingmachine motors, etc. within the sewing factory, optical fibers are usedfor the communication lines to carry out communications through lighttransmission. The communications are performed by a full-duplex system.The communication system uses the polling selecting method wherein thecentral device 40 takes the initiative.

With reference to FIG. 5, the central device 40 and the plurality ofterminal devices 41 are connected together in the form of a loop bylight communication lines. The central device 40 and the terminaldevices 41 respectively include communication control units 45 and 46each having two pairs of sending and receiving terminals S and R, towhich a pair of communication channels A and B is connected. Eachcommunication channel A or B includes a sending line and a receivingline. Each terminal device 41 on the communication loop is connected toother terminal devices 41 immediately adjacent thereto, or to anotherterminal device 41 and the central device 40 which are immediatelyadjacent thereto. The same message (data) is transmitted through thecommunication channels A and B at all times. Since the same message isthus transmitted through the pair of transmission channels A and B, thecentral device 40 can communicate with all the terminal devices 41 evenwhen a failure occurs at one portion of the communication lines.Further, even if one of the communication control units 46 malfunctions,the terminal devices 41 other than the one with the faulty unit 46 cannormally perform communications with the central device 40. While thecentral device 40 is performing a communication with the terminaldevices 41, any terminal device 41 or the communication line can berepaired or removed from the loop, or a new terminal device can be addedto the loop.

FIG. 6 schematically shows the construction of the communication controlunit 45 or 46. While the same message is transmitted through bothcommunication channels A and B, there is generally a slight lag betweenthe time when the message through the channel A arrives at the unit andthe time when the message through the channel B reaches the unit, sothat the message data is likely to change if the two messages aresuperposed simply. To avoid this problem, the communication control unitis provided with a first arrival preference circuit 49.

The outgoing signal (message) from a terminal device or the like is fedto electro/optic (E/O) conversion circuits 47A, 47B, in which the signalis converted to an optical signal, which is then sent out through thethe sending lines of the channels A, B at the same time.

The optical signal fed to an opto-electric (O/E) conversion circuit 48Ais converted to an electric signal, which is sent to the first arrivalpreference circuit and to the E/O conversion circuit 47B of the channelB. From the circuit 47B, the signal is sent out through the sending lineof the channel B. When such an optical signal is received by an O/Econversion circuit 48B of the channel B, the signal is converted to anelectric signal and sent to the preference circuit 49. The electricsignal is also sent to the E/O conversion circuit 47A, in which it isconverted to an optical signal and sent out through the sending line ofthe channel A. In this way, the signal received from the channel A isimmediately sent out through the sending line of the channel B, whilethe signal received via the channel B is immediately sent out throughthe sending line of the channel A to realize duplex loop communications.Since the received optical signal is converted to an electric signal,which is sent out via a sending line upon conversion to an opticalsignal, the O/E and E/O conversion circuits serve as intermediate orrelay devices, with the result that there is no need to consider theproblem of attenuation of optical signals even if the loop communicationlines have a large length Also, even if the preference circuit 49malfunctions the signal received by the O/E conversion circuit is fed tothe E/O conversion circuit and sent out to a sending line. Thus, thecommunication through the loop will not be interrupted.

When signals are received by the preference circuit 49 via the O/Econversion circuits 48A, 48B, the circuit determines which of thesignals is the first to arrive, whereupon the circuit 49 delivers theearlier signal as the received signal. The delayed signal is prohibitedfrom passing through the circuit 49. While receiving signals, thepreference circuit 49 emits an in-communication signal, which is sent tothe CPU of the terminal device or the like. While receiving this signal,the CPU stops transmission of outgoing signals. The outgoing signal isfed to the E/O conversion circuits 47A, 47B as stated above, so thatwhen there is an incoming signal from the O/E conversion circuits 48A,48B to the E/O conversion circuits 47A, 47B, the outgoing signal wouldotherwise be superposed on the incoming signal.

The Terminal Device

FIG. 7 shows the appearance of the terminal device provided at the workarea 32, 33 or 35. Provided on the front side of the case of theterminal device 41 are a power supply lamp 81, an operation lamp 82 forindicating that the device 41 is in normal operation, an input lamp 83for indicating that a bar code input can be received and an error lamp84 for indicating an error in connection with the bar code input. Alsoprovided are a cancel button switch 87 for cancelling the input given bythe output counting switch 42 or 43, and an overtime work button switch88 which is used when the worker works overtime. In the vicinity ofthese button switches, there are pilot lamps 85 and 86 which go on whenthe corresponding switch is depressed. The lamps 81 to 86 comprise, forexample, a light-emitting diode.

The terminal device 41 is provided with a bar code reader 91, which isused for entering the name of an article (product name), process nameand worker name, i.e., codes representing these names. FIG. 10 shows aproduct name-process name card C1 and a worker name card C2. The formercard C1 is issued by the central device 40 and given to the work areaconcerned when a process is set for the work area by the central device40 when work is to be started for a particular day or when theproduction of a new article is to be started. The card C1 bears a barcode representing the name of the article (inclusive of article number,type number, etc.) for which work is to be done at the area concerned,and the name of the process for which work is to be done. The bar codemay further contain a work area code. The worker name card C2, which isspecific to each worker, bears a bar code representing the name of theworker who carries the card C2. The worker name card C2, which iscarried by the worker at all times, is preferably coated with atransparent resin or the like. The card C2 can also be issued by thecentral device 40.

With reference to FIG. 7, the case of the terminal device 41 is providedwith a holder 93 for the bar code reader 91. As seen in FIG. 8, theholder 93 includes a tube 94 for holding the reader 91. The tube 94 hasan open bottom. The holder 93 is provided with a switch 92 for detectingwithdrawal of the reader 91 from the tube 94 of the holder 93. Theswitch 92 is off while the reader 91 is inserted in the tube 94 and isturned on when the reader 91 is withdrawn. A limit switch, photoelectricswitch or the like is usable as the withdrawal detecting switch 92. Theholder 93 is fixedly provided at its bottom with a permanent magnet 93a,by which the holder 93 can be attached to a desired portion of the metalcase of the terminal device 41. The device 41 further has an alarmbuzzer 95. It is desirable that a holder 99 for holding the productname-process name card C1 be provided on the front side of the case ofthe device 41.

FIG. 9 generally shows the electric construction of the terminal device41. The terminal device 41 is controlled by a CPU, such as amicroprocessor 100 which is provided with a ROM 101 having a programstored therein for the CPU and a RAM 102 for storing required data.Connected to the CPU 100 are the communication control unit 46 forperforming communication with the central device 40, the foregoingindicating lamps, button switches and like input-output means. Theinput-output means for the CPU 100 include a terminal address setter 97,a sewing machine relay 97 for turning on or off the power supply forpower sources for various kinds of work, such as sewing machine motors,buzzer 95, lamps 81 to 86, button switches 87, 88, output countingswitch 42 or 43, bar code reader 91 and withdrawal detecting switch 92.The terminal address is used for communications with the central device40. The terminal address setter 97 comprises, for example, eight DIPswitches The address is expressed in an 8-bit binary numbercorresponding to on-off states of these switches The states of the eightswitches are read by a terminal address setting input circuit 111. Thesewing machine relay 96 and the buzzer 95 are controlled and driven by acontrol circuit 112. The indicating lamps 81 to 86 are turned on or offor flickered under the control of a display control circuit 113. Theinput signals from the switches 87, 88, the output counting switch 42 or43, the bar code reader 91 and the withdrawal detecting switch 92 havetheir waveform shaped by circuits 114 to 117, respectively and are fedto an interrupt control circuit 118. The input signals from the switches87, 88, the switch 42 or 43 and the switch 92 serve as interrupt signalsfor the CPU 100. The interruption by the detecting switch 92 is giventhe highest order of priority. The interface circuits 111 to 113 and 118(shown as I.C.) between these input-output means and the CPU areconnected to the CPU 100 by bus lines via an address buffer (A.B.) 103,a data buffer (D.B.) 105 and a control buffer (C.B.) 106. The addresssignal to be given to the address buffer 103 is decoded by an addressdecoder (A.D.) 104 and converted to a signal for specifying theinterface circuits 111 to 113, 118.

The RAM 102 connected to the CPU 100 has an area for storing thecommunication address of the terminal device read from the addresssetting input circuit 111, an area for use as an output counter, an areahaving a flag F for use in cancelling the output count input, an areafor storing process control basic data such as the product name, processname, worker's name, output, etc., and the like. The basic area datastores only the data on the work area in which the terminal device isinstalled.

FIG. 11 shows the usual operation of the terminal device 41. Usually,the device 41 performs processing for communications with the host CPU120 (see FIG. 13) of the central device 40 and output count processing.More specifically, the CPU 100 checks at all times whether a poll orselect message is given to its own address from the central device 40(step 201), whether there is an ON input from the output count switch 42or 43 (step 202), and whether a cancel input is fed from the cancelswitch 87 (step 203). When a poll message is received from the centraldevice 40, the terminal, if it has the data to be transmitted to thecentral device, responds to the inquiry with the data. For example, amessage containing a count of output (value counted by the outputcounter), data read by the bar code reader 91, and the receipt of aninput from the overtime work switch 88 is prepared and sent to thecentral device 40. If there is no data to be sent, a response message tothis effect is forwarded to the central device 40. If a select messageis received, the terminal answers the inquiry as to whether it is readyfor receiving data from the central device 40 (steps 204, 205). The datato be derivered from the central device 40 includes set or changedproduct name, data relating to the process name, process control basicdata, etc.

When the output counting switch 42 or 43 gives an interrupt input, thecount on the output counter advances by 1, and the flag F is reset(steps 206, 207). By this procedure, output is counted at the work areaWhen there is an interrupt input from the cancel switch 87, 1 issubtracted from the count on the output counter only when the flag F isreset (step 208), and the flag F is set (step 210). Upon setting of theflag F, the cancel lamp 85 is turned on. The flag F remains set untilthe next interrupt input is fed from the output count switch 42 or 43(steps 206, 207). Accordingly, even if the worker depresses the cancelswitch 87 twice in succession, the flag is in the set state when thesecond input is given (step 208), so that 1 will not be subtracted fromthe count again.

When there is a change of worker, the output count of the replacedworker is transferred to a specified area, the counter is then clearedand the counting of the output of the incoming worker is started.

As already stated, the counting switch 42 is provided on the outgoingrail 52 of the branch line 22 at a location downstream from thefirst-stage stopping device 58, so that when the worker becomes awarethat a carrier 25, which has been sent out, should not be counted up,she may remove the carrier 25 from the rail 52 at the position of thestopping device 58 or at a location upstream therefrom. The switch 42then will not count up the carrier 25. However, it is likely that theworker will realize that she should not have sent out the carrier 25after the carrier has passed the position of the switch 42. It is alsolikely that the output counting switch at the work area 33 irrelevant tothe conveyor line will be actuated by error. The cancel switch 87 isprovided to meet such a situation, i.e., to assure accurate counting ofoutput.

The product name and process name are set or changed by the operator atthe central device 40. When the product name and process are set orchanged, the above-mentioned product name-process name card C1 isprepared for each work area and given to the worker at each area.Further the set or changed product name and process are transmitted fromthe central device 40 to each terminal 41. Preferably, cards C1 aredistributed as held and transported by carriers 25 on the conveyor line.When the card C1 is delivered, the worker at each work area enters the-card data by the bar code reader 91. The entered product name andprocess name data are sent from the terminal device 41 to the centraldevice 40 for acknowledgement, while the terminal 41 checks the inputdata with the data already delivered from the central device 40.

The data relating to workers' names is entered solely by the terminals41. When starting a day's work or in the event of a change of worker,the worker at each work area enters the data on her own worker name cardC2 with use of the bar code reader 91. The input name data istransmitted from the terminal device 41 to the central device 40. Toassure the principle of "right person in right place," or for somepersonal reason, or to assure a balance between processes, the worker atthe work area changes relatively frequently. Accordingly, it isdifficult for the operator at the central device 40 to recognize changesof many workers without the aid of a computer. With the present system,every time the worker changes at each work area, the terminal device 41sends data as to the change to the central device 40, eliminating theneed for the central device operator to enter the data as to workers'names and permitting the central device to recognize the data.

The terminal device 41 always performs processing for communication withthe central device 40 and output counting processing as already stated.The input processing for product name, process name and worker name,although done only sporadically, is to be given the highest preference.Whenever the worker enters the product name, process name and her namewith use of the bar code reader 91, she grasps the reader 91. Theterminal is therefore adapted to perform the input process utilizing themanipulation of the reader 91 by the worker. When the reader 91 iswithdrawn from the holder 93 in which it is usually inserted, thewithdrawal detecting switch 92 is turned on. Based on the ON signal fromthe switch 92, the interrupt control circuit 118 feeds an interruptsignal to the CPU 100. The interruption by the switch 92 is given thehighest preference as already stated, so that the CPU 100 immediatelyexecute an interrupt process.

Thus, the bar code reader holder 93 is provided with the withdrawaldetecting switch 92, and an interrupt signal is produced in response tothe detection signal from the switch to assure an interruption with thehighest preference. This eliminates the necessity for the CPU 100 toalways check on the program whether there is an input from the bar codereader 91, consequently ensuring the CPU 100 of an efficient operation.If the withdrawal detecting switch 92 were absent, the worker would haveto depress a specific switch for entering the product name, process nameand her name to enter an interrupt signal. However, with an automaticinterruption effected by the switch 92, the worker merely needs to graspthe reader 91 to immediately follow the procedure of reading the barcode, which is a very simple procedure.

FIG. 12 shows interrupt processing following the detection ofwidthdrawal of the bar code reader. Upon the detection of the withdrawalof the reader 91 by the switch 92, the input lamp 83 goes on, indicatingthat the reader 91 has been withdrawn. At the same time, the relay 96turns off the power supply to working machine such as sewing machine(step 211). Before a period of time, e.g., several seconds to tens ofseconds, elapses, the bar code on the card C1 or C2 is scanned by thereader 91 handled by the worker and is thereby read (steps 212 to 214).The bar code data read is then checked (step 215). When the product nameand process name are set or changed, the set or changed data has alreadybeen delivered from the central device 40 to the terminal device 41, sothat the data as to the product name and process name forwarded to theterminal 41 from the device 40 is compared with the read data forchecking whether the two items of data match. If the data items do notmatch, an error has occurred. In reading the card C1 or C2, the readdata is also checked as to the format, etc. to check whether the card isa proper one. Whether the code is read without error is also checked. Ifthere is no error, and the bar code reader 91 is thereafter insertedinto the holder 93, the switch 92 is turned off (step 217), whereuponthe lamp 83 goes off, and the machine power supply is turned on (step218). The bar code reading procedure thus completed is followed by theusual operation again. The worker resumes the specified sewing work.

When the bar code reader 91 is withdrawn and then re-inserted into theholder 93 without scanning any bar code, the lamp 83 similarly goes off,and the machine power supply is turned on (steps 222, 223).

If there is some error when the bar code is read, the error lamp 84flickers, and the buzzer 95 gives an alarm (step 220), whereupon theworker follows the bar code reading procedure again.

When there is no input of read data from the reader 91, despite thelapse of the above-mentioned period of time after the withdrawal of thereader 91, and also when the reader 91 is not returned to the holder 93despite the lapse of the above period of time, the error lamp 84flickers and the buzzer 95 goes on (steps 212, 219; 221, 219). Thismakes the worker aware that the bar code has not been read or that thereader 91 has not been inserted in place, whereupon the worker followsthe specified procedure.

Also when the bar code reader 91 becomes removed from the holder 93 forone cause or another, the lamp 83 goes on, and the machine power isturned off (step 211). A specified period of time thereafter, the lamp84 flickers and the buzzer 95 goes on (step 219), notifying the workerof the removal of the reader 91.

The terminal device 41 has the input lamp 83 and the error lamp 84, andthese lamp go on according to the state of the reader 91. Thismanifestly indicates the state of the reader and makes the reader easyto use, while notifying the worker of a fault, if any. Consequently, anerror in procedure or an abnormality will not be left uncorrected.Especially because the detection of withdrawal of the bar code reader 91is followed by an interruption procedure, the usual operation of theterminal device 41, i.e., processing of communication with the centraldevice 40 and output counting processing, will not be effected properlyif the reader is left withdrawn for a long period of time. However, sucha situation is avoidable by the above expediency.

The Central Device

FIG. 13 generally shows the electric construction of the central device40. The device includes the host CPU 120, which has a memory 121 havinga program stored for the CPU and a data memory 122 for storing variousitems of data for controlling the sewing process. Connected to the hostCPU 120 through a suitable interface 127 are a keyboard (including alight-pen) 123 for entering data or instructions for setting purposesand giving outputs, a CRT 124 for displaying various items of data, suchas outputs, for sewing process control as will be stated later, aprinter 125 for printing out such data and for preparing the cards C1,C2, and an alarm buzzer 126. The foregoing communication control unit 45is also connected to the CPU. The data memory 122 has an area (databuffer) for storing basic data for the sewing process control, an areafor storing a series of processes set under each product name andtotaling outputs as classified by product names and processes, an areafor totaling outputs as classified by individual workers, an area forcommunication with terminals, an area for storing character codes fordisplaying or printing names of products, processes and workers, incorresponding relation to these names, and other areas. The memory 122has stored therein, in addition to the above data, series of processesset before or until the previous day, standard pitch time data fortypical processes, etc. The process data in the past is used as basic orreference data when setting new processes.

FIG. 14 schematically shows the operative relation between the centraldevice 40 and the terminal device 41. This diagram shows the generalflow of operation of the central device 40 at left, and that of theterminal device 41 at right. Before the start of operation at the sewingfactory, the power supply for the central device 40 is turned on in themorning, whereupon the host CPU 120 checks whether the device 40operates normally, by self-diagnosis test (step 231). Confirmation ofthe date and time is followed by a communication test with each terminaldevice 41 (step 232). For this test, the central device 40 transmitstime data to the terminal 41, which in turn returns the same time datato the central device 40.

The power supply for the terminal device 41 is continuously on at alltimes and need not be turned on by the worker. The terminal device 41,operating in standby mode, is adapted to be brought into the operationillustrated in FIG. 14 in operative relation with the closing of themain power supply switch of the sewing factory. As is the case with thecentral device 40, a self-diagnosis routine is executed first (step241). Upon receiving the time data from the central device 40, the clocktime of the terminal 41 is adjusted to match the clock time of thecentral device 40 (step 242). In this way, all terminal devices 41 areset to the same clock time. Subsequently, the RAM 102 is cleared of theprevious day data, such as basic data, and the output counter is cleared(step 243). In response to a request for data by the central device 40,the terminal device sends the time data already received to the centraldevice 40 (step 244).

When the central device 40 receives from a terminal device 41 the sametime data as was sent to that device 41, the central device judges thatthe terminal and the communication is in normal operation. If some errorhas occurred, transmission of the time data is repeated three timesbetween the central device 40 and the terminal device 41. If the errorstill remains despite three repetitions of such as communication, it isjudged that the terminal concerned or the communication system isfaulty, and the CRT 124 shows this result. The faulty terminal device isrepaired or removed.

Next, at the central device 40, the operator sets a product name andprocesses for the work of the day (step 233). In other words, to eachwork area in the sewing factory, the work (process) to be performedthere is assigned. If the previous day work is to be resumed, theprocess setting data for the previous day will be used as it is. Asimple modification may be made in some cases. Process setting data fromthe past may be utilized as it is or as slightly modified, or totallynew processes may be set. In any case, area codes are displayed on theCRT 124 as seen in FIG. 16, and a series of processes are set byentering the contemplated process name and product name for each areacode using the keyboard or light-pen. The set processes are stored inthe basic data area, etc., of the memory 122. Preferably, processsetting is made on the previous day, in which case step 233 onlyconfirms the setting. In accordance with the set process, a worker isassigned to each work area. In this stage, the name of the worker hasnot been entered in the central device 40, because the worker's name isentered in the terminal device at each work area with use of the workername card C2 a already described.

After product and process name setting, the set product name and processname are printed out in the form of a bar code by the printer 125 toprepare a product name-process name card C1 for each work area (step234). The cards C1 thus prepared are distributed to the work areas orworkers by working personnel or utilizing the conveyor system. Theproduct name and process name assigned to each work area are sent to theterminal device 41 concerned (step 235).

At each terminal 41 of work area, the bar codes on the distributed cardC1 and the worker name card C2 carried by the worker are read by thereader 91 (step 245). The product name and process name thus entered bythe reader 91 are checked with those sent forward from the centraldevice 40 as described above. If there is a request for data by thecentral device 40 (step 235), the product, process and worker name dataread by the reader 91 is sent from the terminal 41 to the central device40 (step 246).

Upon receiving the above data from the terminal 41 in response to therequest, the received data is checked with the data of already setproduct name and process name (steps 235, 236). The worker name datatransmitted from each terminal device 41 is stored in the basic dataarea of the memory 122. If an error is found in the names forwarded fromthe terminal device 41 or no name data is received, the terminal 41 isurged or instructed to send the data or enter the data again. In such acase, the error lamp 84 flickers or the buzzer 95 goes on (step 247).

The processing for the start of work is thus completed. The terminaldevice 41 thereafter performs the aforementioned usual operation, i.e.,output count processing and transmission of count data, etc., to thecentral device (steps 248, 249). When the overtime button switch 88 isdepressed at 16:45 or later for overtime work, the central device 40 isnotified of this by the terminal device 41 (step 250).

The central device 40 requests the terminal device 41 to send data, at agiven time interval, e.g., every several minutes, and processes andstores various data, such as output counts, forwarded from the terminal(steps 237, 238). The central device 40 performs (electrical) outputprocessing (step 239) to display on the CRT 124, or print out by theprinter 125, various items of process control data in response toinstructions keyed in by the operator with the keyboard 123.

FIG. 15 shows typical examples of (electric) output processingprocedures (FIG. 14, step 239) performed by the central device 40. Theseexamples are as follows. In step 261 of (electric) output processing fordisplaying or printing output (i.e., amount of work done), the output(work amount) as classified by products, processes and individuals orworkers is displayed on the CRT 124 or printed out by the printer 125 inthe form of a graph or table. Each process output to be obtained in aspecified period of time, e.g., one hour, is calculated and delivered asan electric output by step 262 of processing for output estimation. Thevariation of output between processes is determined and delivered as anelectric output by step 263 of processing for line balance check. Inworker daily report output processing (step 264), data relating to thedaily work of each worker and evaluation thereof is prepared anddelivered as an electric output. Data as to the proficiency of eachworker is prepared and delivered by step 265. Other processing is alsoperformed (step 266).

Processing for Displaying or Printing Output (work amount)

FIG. 17 shows part of the basic data area of the data memory 122 of thecentral device 40. This data area stores all data relating to one day'swork at each work area within the sewing factory. For the area code ofeach work area, there are locations for storing state flags, productname codes, process codes, worker name codes, outputs, actual pitch timevalues, standard pitch time values, actual work hours, etc. The stateflag is used to show the host CPU 120 the data of which of these storagelocation is (was) written, retrieved or otherwise handled. Since it islikely that a plurality of product names or process names will be setfor a day at one work area, a plurality of product name codes and aplurality of process name codes can be stored. One process may bepracticed by at least two workers alternately, so that a plurality ofworker name codes can be stored. These name codes are stored asassociated with the product name and process name codes. The output isstored according to time zones which are divisions of a day. With thepresent embodiment, the time zones are 8:15- 10:00, 10:00-12:00,12:00-15:00, 15:00-16:45 and after 16:45. For the sake of simplicity,these times zones will be referred to as 10:00, 12:00, 15:00, 16:45 andovertime time zones. The output during each time zone is stored asassociated with worker name code. The term "actual pitch time" means theperiod of time actually taken for a worker to perform the work of oneunit of a process. To explain this in connection with the conveyorsystem: the actual pitch time is the period of time from the delivery ofone carrier, until the delivery of the next carrier during which timethe article on the latter carrier is worked on. This pitch time ismeasured by factory personnel. The actual pitch time is used forcalculating a theoretical output and line balance check. The term"standard pitch time" refers to a standard period of time required forperforming the work of one unit of a process and generally is determinedstatistically. The actual work time is the period of time during which aworker actually works. One day's actual work time is obtained bysubtracting the recesses during the day from the sum of the time zones.Actual work time during each time zone, which is obtained by subtractingthe recess during the time zone from the time zone period, and theactual work time of each worker, are also stored. The standard pitchtime and actual work time are used for calculating the proficiency ofeach worker. The actual pitch time and actual work time are stored asassociated with the worker name code, and the standard pitch time withthe process code. The actual pitch time and standard pitch time areentered by the operator with use of the keyboard 123. As to the standardpitch time, the corresponding data in the past stored in the memory 122for the same process is usable.

The basic data area within the RAM 102 of the terminal device 41 alwayshas stored therein data as to the work area in which the terminal 41 isinstalled, and this data is identical with all the data stored for thatarea in the basic data area of the memory 122 of the central device.Accordingly, even if one of the memories becomes faulty, the data can becompletely backed up.

FIG. 18 shows the outline of the usual processing for displayingoutputs. Output display includes display of output as classified byproduct names, display of output by processes for one product, enlargeddisplay of output by processes, and display of output as classified byindividuals (workers) for one product in one process. When an outputdisplay instruction is given by the keyboard 123, the output by productnames is first shown on the CRT 124. From the basic data area of thememory, each process code and output for each kind of product aretransferred to work areas. The output (according to time zones) of thefinal process, e.g. ironing process, is searched for for each product,and the output sum of the final process up to the current time iscalculated (step 271). The output sum of the final process representsthe number of finished products of the particular kind. As seen in FIG.19, the final process output sum of each product name is displayed inthe form of a graph and table on the CRT 124 (step 272). In the graphand table, like products are referred to by like product name numbers.The CRT 124 also shows the date and time of display. In the bar graph ofFIG. 19, the output up to 10:00 is represented by a blank portion, theoutput up to 12:00 by a hatched portion, the output up to 15:00 by amesh portion, and the output up to the display time by a solid portion.These portions are shown in different colors.

When one of the products shown is specified by the keyboard or light-pen(step 273), the outputs of all processes for the specified product aresearched for, and the sum of outputs of each process as classified bythe time zones is calculated (step 274). The data thus retrievedincludes: the output (sum) "a" during 10:00 time zone, sum "b" which isthe output "a" plus the output of 12:00 time zone, sum "c" which is thesum "b" plus the output of 15:00 time zone, and sum "d" which is the sum"c" plus the output of 16:45 time zone up to the display time. As seenin FIG. 20, these sums "a" to "d" are graphically shown on the CRT 124in different colors for each process represented by a process number(step 275). In FIG. 20, the two-dot-and-dash line, one-dot-and-dashline, dotted line and solid line are, for example, red, blue, yellow andwhite. The display of output by processes manifestly indicates theprogress of work (line balance) for the specified product.

The four sums "a" to "d" are shown in FIG. 20 since the display is givenat 16:10. The display, if given for example at 14:00, includes the sums"a" and "b" and a sum "c1" which is the sum "b" plus the output of 15:00time zone up to 14:00. When the display is given during the overtimetime zone, the output of 16:45 time zone plus the overtime output willbe shown. The output by processes may be displayed in the form of atable. When another product is specified, the process outputs of thenewly specified product will be similarly shown (steps 273 to 275).

When the operator desires to see some process portions of theprocess-wise output display, the operator specifies the range ofportions to be enlarged (the number of processes included in the rangeis predetermined) or the main process within this range by the keyboardor light-pen (step 276), whereupon the process names of the specifiedrange and the outputs thereof are retrieved (step 277), and the outputsof a plurality of processes are displayed in the form of an enlargedgraph on the CRT 124 as shown in FIG. 21 (step 278). The sumscorresponding to the sums "a" to "d" are shown in different colors as inthe case of FIG. 19.

When it is desired to view the details of one of the plurality ofprocesses thus displayed, the desired process (for the specifiedproduct) is specified (step 279), whereupon the output of the product asclassified by workers for the process is retrieved (step 280). FIG. 22shows the data thus retrieved in the form of a table, revealing theproduct name, process name, worker's names and individual (worker)outputs achieved up to the display time (step 281), i.e., display ofoutput by product, process and workers

It is of course possible to print out by the printer 125 the variousitems of output data shown in FIG. 19 to FIG. 22.

FIG. 23 shows a further detailed example of output display, in whichindividual worker outputs are shown in detail as classified according tothe kind of product, process name and time zone in detail. First, theoperator specifies the desired product and process (step 291). Furtherthe actual pitch time and actual work time for the process are entered(step 292). The actual work time may be calculated by the CPU 120. Theoutput of the specified product and process is retrieved and therequired data is prepared and shown on the CRT 124. FIG. 24 shows theoutput data as classified by processes and time zone for the particularproduct on the display. If required, the data is printed out by theprinter 125 (steps 293, 294). FIG. 24 shows the data which is obtainedon completion of one day's work. When the work of one process isconducted at a plurality of work areas, the data as to all the area forthe same process is displayed. When a plurality of workers work at onework area, data as to each worker is displayed. In any case, output isobtained for each the workers working for the same process, the outputincluding the work area code, process name, output and sum thereof ineach time zone, actual pitch time, theoretical output calculated withuse of the pitch time, and the difference between the theoretical outputand the output sum of each worker for the day (excess or deficit). Thetheoretical output is determined by dividing one day's actual work timeby the actual pitch time.

Such detailed data is given not only on completion of daily work butalso at a desired time specified by the operator and furtherautomatically periodically, e.g., at 10:00, 12:00, 15:00 and 16:00. Atsuch a point in time, the output up to that time will be given asclassified by time zones. If the actual pitch time is not fed, thetheoretical output or excess/deficit will not be given.

Processing for Output Estimation

Processing for Output Estimation: that for process-wise estimation, bywhich the output to be obtained one hour later from each process iscalculated and displayed for one product. FIG. 25 shows the outline ofthe processing procedure. For the specified product, the pitch time iscalculated for each process with use of the basic data in the memory 122(step 301). The pitch time is obtained by dividing output by actual worktime. The output and actual work time to be used for this calculationare the data of the immediately preceding time zone. For example, forthe output estimation to be made during 10:00 to 12:00, the output andactual work time during 10:00 time zone are used. For the estimation tobe made during the period of 12:00 to 15:00, the output and actual worktime of 12:00 time zone are used. The reason is that the work efficiencygenerally increases with time; it is higher in 12:00 time zone than in10:00 time zone. It is higher in 15:00 time period and still higher in16:45 time zone. No output estimation is done during the period of 8:15to 10:00.

Next, for each process, one hour (60 minutes) is divided by thecalculated pitch time to obtain an estimated output that would beobtained in one hour. The output sum to be obtained one hour later iscalculated by adding the calculated estimated output to the output sumup to the current time concerned (step 302).

FIG. 26 graphically shows the output sum achieved by the indicated time(broken line) and estimated output sum to be achieved in one hour foreach process (indicated by process number). The data is shown on the CRT124 in different colors (step 303). The display shows the operator theoutput sum to be obtained in one hour.

In addition to the mode of display shown in FIG. 26, product-, process-and worker-wise output estimations can be displayed in the same manneras in FIGS. 19, 21 and 22. The estimated output data can of course beprinted out by the printer 125. The estimation processing shown in FIG.25 is preferably performed as associated with the output displayprocessing of FIG. 18. For example, the display of output by products(steps 271, 272 in FIG. 18) can be followed by product-wise outputestimation, and the process-wise output display (FIG. 18, steps 273 to275) can be followed by the processing of FIG. 25.

Output estimation is useful for production control in determining whento set processes for a new product to be made subsequent to the currentproduct, or in judging whether the product to be delivered can bemanufactured in time.

Processing for Line Balance Check

FIG. 27 shows an exemplary procedure for line balance check, wherein alldata is entered by the operator. First, allowable upper and lower limitsfor line balance are set (step 311). The upper and lower limit valuesare expressed, for example, as 80%-120%, or 0.9-1.1. The upper and lowerlimit values may be preset in the memory 122. Subsequently, the actualpitch time of the process is entered to be a reference for the productfor which the line balance is to be checked (step 312). The actual pitchtimes of other processes for the same product are also entered (step313). The reference process is a process which serves as a reference inchecking the output balance between processes. While the final process(e.g., an ironing process) is generally used, any desired process isserviceable as the reference. The actual pitch time is measured by theoperator as to all the processes or a required number of processes priorto the present processing. When the present procedure is to be performedfor a plurality of products, the actual pitch time of processes for eachproduct is entered. As to the method of pitch time data input, the datacan be entered for all processes first, and the reference processthereafter specified.

With the required data thus entered, a balance factor is calculated forevery process. The balance factor is obtained by dividing the output(theoretical) of a process during a specified period of time (e.g., onehour) by the output (reference output) of the reference output duringthe same period of time. For the sake of convenience, the balance factoris expressed as a percentage in the case of the present embodiment. Theoutput during a given time period of processes, inclusive of thereference process, can be determined by dividing the time period by theinput actual pitch time. Accordingly, the balance factor can also becalculated directly from the actual pitch time. When a process name isspecified by the operator, the CRT 124 displays data such as the processname, the product name concerned, reference output, theoretical output,balance factor of the process and whether the factor is within theallowable range dependent on the upper and lower limits as seen in FIG.28 (step 314). When the balance factor is in this range and further whenthe next process is specified, the same display as above is given forthe next process (steps 315, 316). If the balance factor is not withinthe allowable range, the image screen of the CRT 124 changes entirely analarm color such as red or yellow, and the buzzer 125 goes on (step317).

When displays are given for all processes for all products and a desiredproduct name is then specified, the process-wise balance factors for theproduct are displayed on the CRT 124 as shown in FIG. 29. The graphshows the apparent balance of the overall process. The upper and lowerlimits are also shown. When required, the line balance data is printedout by the printer 125.

The line balance check process can also be executed with use of theactual outputs stored in a reference data area in the memory 122,instead of the actual pitch time. In this case, the output as the basisfor determining the line balance factor can be the output of a desiredtime period, e.g., the output sum from 8:00 a.m, or the output of thetime zone immediately preceding the check procedure, or the outputduring a given period of time (e.g. 1 hour or 30 minutes) immediatelypreceding the check procedure. The foregoing estimated output may alsobe used for determining estimated line balance.

The line balance check procedure may be performed at all times by theCPU 120 to automatically give an alarm when a process is found which isoutside the allowable range of upper and lower limits.

It is possible to carry out the line balance check processing asassociated with the foregoing processing for output display orestimation.

The output variation between processes, if smaller, results in a highersewing efficiency. When there is a process which is exceedingly smalleror greater than the reference process in output, intentional adjustmentmust be made, for example, by changing the worker or using an increasednumber of work areas. The line balance check process reveals an outputvariation between processes, so that such adjustment can be accomplishedeasily.

Worker Daily Report Processing

Data as to the amount of work done by each worker for the day and dataas to the evaluation thereof ar prepared and given as an output. Thisprocedure is performed generally upon completion of one day's work. FIG.30 shows part of the worker daily report printed out by the printer 125.Printed on the report for each worker are the name(s) of the product(s)for which she worked on that day, the name(s) of process(es) concerned,the day's out-put of each process, the standard pitch time (min) of eachprocess, standard work hour (min) and actual work hour (min),proficiency of the worker in each process (%), and total or average ofsuch values. The actual work hour or time is the period of time which isthe period from the start of work for the process to the end of work,minus recesses (predetermined as to the duration and time zone). Thestart and ending of work can be determined by reading the worker namecard, process setting or the like. The standard work hour or time is theoutput multiplied by the standard pitch time. The proficiency isobtained by dividing the standard work time by actual work time. Whenthe worker engaged in one process only during the day concerned, theproficiency for the process is the average of the proficiency on thatday.

The worker daily report indicates the aptitude and proficiency of theworker for the work. Furthermore, the report serves as data forevaluating her service and provides basis for calculating wages when sheworks on a piece rate.

The average value of proficiency degree of each worker is stored alongwith the date in a worker totaling area of the memory 122 (see FIG. 31.)The proficiency data is used later for worker proficiency dataprocessing. In place of the average proficiency value, the degree ofproficiency for each process may be stored.

The data as to individual workers other than the proficiency data neednot always be held stored in the memory 122 after printing by theprinter 125. This saves the storage space within the memory.

Worker Proficiency Data Processing

When a worker's name is specified and an output instruction is given bythe keyboard and light-pen, the proficiency data (average values) storedin the memory 122 as shown in FIG. 31 is displayed in the form of agraph on the CRT 124 as seen in FIG. 32. In the graph, the date isplotted as abscissa vs. the proficiency as ordinate. The graph readilyindicates the proficiency of the worker. The CRT 124 also shows anacceptable proficiency line P. The proficiency data can be printed outby the printer in the form of a graph or table. When the proficiencydata is stored for each process, like graph can be displayed and printedout for each process. The proficiency data is very useful for assigningsuitable work to workers and work training or guidance.

Other Processing

Other processing includes the procedure of handling faulty products the,procedure of cost accounting, etc.

Identification of Abnormal Terminal Device

Since the central device 40 and all terminal devices are connectedtogether by communication channels in the form of a loop, a malfunctiondeveloping in one terminal influences the other terminals to possiblyresult in a failure of the system. With the present communicationsystem, when one terminal device has failed, the other terminal devicesare still capable of communicating with the central device However, itis not desirable to leave the faulty terminal as it is. If a terminalfails while performing a specified operation such as counting of outputat the work area, it becomes impossible to collect the data as to thatwork area, with the result that the data prepared by the forgoing outputprocessing, line balance processing, etc., will not be perfect. Theabnormal terminal identifying processing detects faulty terminalspromptly and takes corrective measures.

FIG. 33 shows part of the communication area provided within the memory122 of the central device 40, namely an abnormal terminal table Thetable has an abnormality flag in corresponding relation to the terminaladdress (or other suitable identification symbol) of each terminal. Thecommunication area includes a location which is used as a scanningcounter.

FIG. 34 shows the communication process to be executed by the host CPU120 of the central device 40 with terminal devices The process isperformed for the communication test before the start of operation shownin FIG. 14 (step 232), for communication to confirm process name, etc.(steps 235, 236) and for the usual communication (steps 237, 238).First, numerical data, e.g., terminal address, is set on the scanningcounter for specifying the first terminal device (step 321). Next, theabnormal terminal table is searched to check whether the abnormalityflag for the terminal concerned is set (step 322). The flag, if set,indicates that the device is abnormal. If otherwise, a poll message (orselect message) is sent to the terminal to wait for a response (step323). When some response is received from the terminal concerned withoutany error (step 324), the response message is processed (step 325), e.g.data check, modification, storage, etc. (FIG. 14, steps 236, 238). Oncompletion of this process, the scanning counter is advanced by 1, andthe terminal address of the terminal device with which communication isto be made next is set on the counter (step 326), which is followed bystep 322 again. The same procedure is repeated in succession. "If thereis no response from the terminal to which a pole message was given, evenupon lapse of a predetermined period of time, or if the responsereceived"; has some error (NO to the inquiry of step 324), a pollmessage is transmitted again. If some fault still remains even whenpolling is repeated three times for the same terminal (YES to step 327),the address number or the like of the abnormal terminal and an incidenceof abnormality are displayed on a portion of the CRT 124 (step 328). Atthis time, the buzzer 126 may be turned on. The address of the abnormalterminal is temporarily stored in a suitable area of the memory. At thistime, the abnormality flag may be set for the faulty terminal, but withthe present embodiment, the flag is adapted to be set by the treatmentto be described later for error terminals. Step 326 thereafter followsfor the communication with the next terminal.

If an abnormality flag is in set position (YES to the inquiry of step322), no communication process is done for the terminal concerned butcommunication with the next terminal immediately follows. Thus, nocommunication is made with the terminal for which the flag is set, sothat improved communication efficiency can be achieved by eliminatingthe useless procedure of communicating with the faulty terminal fromwhich no response whatever would be obtained.

When information as to an abnormal terminal is displayed on the CRT 124,the operator takes counter-measures by repairing the terminal device,removing the terminal from the communication channels (andinterconnecting the channels A and B connected to the terminal), orreplacing the faulty terminal by a new one. The faulty one may beallowed to stand as it is.

FIG. 35 shows the procedure to be thereafter followed by the operator.After the abnormal terminal device has been repaired or replaced by anew terminal, the address or number of the terminal and completion ofrepair is entered by the operator with the keyboard 123 or the like(step 331), whereupon test communication is performed for the terminaldevice (step 332). When normal communication is performed, "An OKsignal" is displayed on the CRT 124 (step 334). If the faulty terminalis replaced by a new one, the basic data relating to the work areaconcerned will be sent to the new terminal from the central device 40.If some error still remains despite repetition of communication testthree times (YES to step 333), the CRT 124 gives the same abnormalitydisplay as in the foregoing step 328 (step 335). At this time theabnormality flag may be set.

When the operator has decided to remove the abnormal terminal devicefrom the communication channels or to allow it as it is, "no need ofrepair" is entered by the operator (step 331), whereupon the abnormalityflag for the terminal is set (step 336), and the terminal is removedfrom the communication routine as stated already. In this disclosure,there is shown and described only the preferred embodiment of theinvention, but, as aforementioned, it is to be understood that theinvention is capable of use in various other combinations andenvironments and is capable of changes or modifications within the scopeof the inventive concept as expressed herein.

We claim:
 1. A system for communicating between a plurality of terminaldevices and a central device connected to said plurality of terminaldevices, wherein the central device comprises:communicating means fortaking the initiative and performing communication with the plurality ofterminal devices in a predetermined order by scanning the terminaldevices and for detecting an abnormality of a terminal device incommunication therewith; an abnormal terminal table in which theabnormality of said terminal devices is registered; means for checkingwhether an abnormality is registered for a particular one of theterminal devices with reference to the table before communicating withsaid particular terminal device and generating a corresponding output;control means responsive to the output of the checking means, forcausing the communicating means to proceed to communication processingwith said particular terminal device when no abnormality is registeredand for causing the checking means to check the next terminal device forabnormality registration when an abnormality is registered; and meansfor registering in said abnormal terminal table any terminal device thatis found abnormal by the communicating means.
 2. A system as defined inclaim 1, wherein:said central device comprises a display unit fordisplaying data pertaining to the abnormal terminal device in responseto detection of the abnormal terminal device by the communicating means.3. A system as defined in claim 2, wherein:said central device comprisesan input unit and means for registering the abnormal terminal device inthe table in response to an abnormality confirming input from the inputunit.
 4. A system as defined in claim 2, wherein:the central devicecomprises an input unit and the control means operates to cause thecommunicating means to conduct a communication test with the abnormalterminal device in response to an input from the input unit, indicatingthat the abnormal terminal device has been completely repaired.
 5. Asystem as defined in claim 1, wherein:said central device comprises aninput unit and means for registering the abnormal terminal device in thetable in response to an abnormality confirming input from the inputunit.
 6. A system as defined in claim 5, wherein:the central devicecomprises an input unit and the control means operates to cause thecommunicating means to conduct a communication test with the abnormalterminal device in response to an input from the input unit, indicatingthat the abnormal terminal device has been completely repaired.
 7. Asystem as defined in claim 6, wherein:said central device comprises adisplay unit for displaying data pertaining to the abnormal terminaldevice in response to detection of the abnormal terminal device by thecommunicating means.
 8. A system as defined in claim 1, wherein:thecentral device comprises an input unit and the control means operates tocause the communicating means to conduct a communication test with theabnormal terminal device in response to an input from the input unit,indicating that the abnormal terminal device has been completelyrepaired.